Light emitting device

ABSTRACT

A light emitting device including a first light emitting part including a first n-type semiconductor layer, and a first mesa structure including a first active layer, a first p-type semiconductor layer, and a first transparent electrode vertically stacked one over another and exposing a portion of a first surface the first n-type semiconductor layer, a second light emitting part disposed on the exposed portion of the first n-type semiconductor layer and spaced apart from the first mesa structure, and including a second n-type semiconductor layer, a second active layer, a second p-type semiconductor layer, and a second transparent electrode, and a first bonding part bonding and electrically coupling the first n-type semiconductor layer and the second n-type semiconductor layer to each other.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/764,961, filed on Aug. 17, 2018, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND Field

Exemplary embodiments of the invention relate generally to a lightemitting device, and more specifically, to a light emitting devicehaving a plurality of light emitting layers stacked.

Discussion of the Background

Light emitting diodes as inorganic light sources are being diverselyused in various fields, such as display devices, vehicle lamps, andgeneral lighting. Light emitting diodes are rapidly replacing existinglight sources due to their longer lifetime, lower power consumption, andfaster response speed.

A display device implements various colors by generally utilizing mixedcolors of blue, green, and red. Each pixel of a display device includesblue, green, and red sub-pixels, and the color of a particular pixel isdetermined through the colors of the sub-pixels, and an image isdisplayed by a combination of pixels.

Light emitting diodes have been mainly used as backlight sources indisplay devices. However, recently, a micro LED display has beendeveloped as a next generation display, which directly displays imagesby using the light emitting diodes.

The above information disclosed in this Background section is only forunderstanding of the background of the inventive concepts, and,therefore, it may contain information that does not constitute priorart.

SUMMARY

Light emitting devices constructed according to exemplary embodiments ofthe invention have excellent light reproducibility.

Additional features of the inventive concepts will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the inventive concepts.

A light emitting device according to an exemplary embodiment includes afirst light emitting part including a first n-type semiconductor layer,and a first mesa structure including a first active layer, a firstp-type semiconductor layer, and a first transparent electrode verticallystacked one over another and exposing a portion of a first surface thefirst n-type semiconductor layer, a second light emitting part disposedon the exposed portion of the first n-type semiconductor layer andspaced apart from the first mesa structure, and including a secondn-type semiconductor layer, a second active layer, a second p-typesemiconductor layer, and a second transparent electrode, and a firstbonding part bonding and electrically coupling the first n-typesemiconductor layer and the second n-type semiconductor layer to eachother.

The second light emitting part may include a second mesa structureincluding the second active layer, the second p-type semiconductorlayer, and the second transparent electrode vertically stacked one overanother, the second mesa structure may expose a portion of the secondn-type semiconductor layer.

The light emitting device may further include a third light emittingpart disposed on the exposed portion of the second n-type semiconductorlayer, and including a third n-type semiconductor layer, a third activelayer, a third p-type semiconductor layer, and a third transparentelectrode, and a second bonding part bonding and electrically couplingthe second and third light emitting parts to each other between thesecond n-type semiconductor layer and the third n-type semiconductorlayer.

A thickness of the second bonding part may be greater than a thicknessof the second active layer.

The first mesa structure, the second mesa structure, and the third lightemitting part may have substantially the same size with each other.

The light emitting device may further include a first pad electricallycoupled with the first transparent electrode, a second pad electricallycoupled with the second transparent electrode, a third pad electricallycoupled with the third transparent electrode, and a common padelectrically coupled with the first, second, and third n-typesemiconductor layers.

The common pad may be disposed on a second surface of the first n-typesemiconductor layer opposing the first surface.

The common pad may be disposed on the exposed portion of the firstn-type semiconductor layer.

The common pad may be disposed on the exposed portion of the secondn-type semiconductor layer.

The third light emitting part may include a third mesa structureincluding the third active layer, the third p-type semiconductor layer,and the third transparent electrode, the third mesa structure may exposea portion of the third n-type semiconductor layer, and the common padmay be disposed on the exposed portion of the third n-type semiconductorlayer.

The light emitting device may further include a third light emittingpart disposed on the exposed portion of the first n-type semiconductorlayer and spaced apart from the second light emitting part, the thirdlight emitting part may include a third n-type semiconductor layer, athird active layer, a third p-type semiconductor layer, and a thirdtransparent electrode.

The light emitting device may further include a second bonding partbonding and electrically coupling the first and third light emittingparts to each other between the first n-type semiconductor layer and thethird n-type semiconductor layer.

The first bonding part may extend between the first n-type semiconductorlayer and the third n-type semiconductor layer, and may bond andelectrically couple the first and third light emitting parts to eachother.

The first mesa structure, the second light emitting part, and the thirdlight emitting part may have substantially the same size with eachother.

The light emitting device may further include a light blocking layerdisposed between the second and third light emitting parts on theexposed portion of the first n-type semiconductor layer.

A thickness of the first bonding part may be greater than a thickness ofthe first active layer.

The second bonding part may be integrated with the first bonding part.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of theinvention, and together with the description serve to explain theinventive concepts.

FIG. 1A is a top view of a light emitting device according to anexemplary embodiment.

FIG. 1B is a cross-sectional view taken along line A-A′ of FIG. 1A.

FIG. 1C is a perspective view a portion of the light emitting device ofFIG. 1A.

FIG. 1D is a cross-sectional view of a light emitting device of FIG. 1Aaccording to another exemplary embodiment.

FIGS. 2A, 2B, and 2C are cross-sectional views of a light emittingdevice according to an exemplary embodiment.

FIG. 3A is a plan view of a light emitting device according to anexemplary embodiment. FIG. 3B is a cross-sectional view taken along lineA-A′ of FIG. 3A.

FIGS. 4A, 5A, 6A, 7A, 8A, 9A, 10A, 11A, 12A, 13A, 14A, 15A, and 16A aretop views for illustrating a method of manufacturing a light emittingdevice according to an exemplary embodiment.

FIGS. 4B, 5B, 6B, 7B, 8B, 9B, 10B, 11B, 12B, 13B, 14B, 15B, and 16B arecross-sectional views taken along lines A-A′ of corresponding tops viewof FIGS. 4A to 16A, respectively.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments or implementations of theinvention. As used herein “embodiments” and “implementations” areinterchangeable words that are non-limiting examples of devices ormethods employing one or more of the inventive concepts disclosedherein. It is apparent, however, that various exemplary embodiments maybe practiced without these specific details or with one or moreequivalent arrangements. In other instances, well-known structures anddevices are shown in block diagram form in order to avoid unnecessarilyobscuring various exemplary embodiments. Further, various exemplaryembodiments may be different, but do not have to be exclusive. Forexample, specific shapes, configurations, and characteristics of anexemplary embodiment may be used or implemented in another exemplaryembodiment without departing from the inventive concepts.

Unless otherwise specified, the illustrated exemplary embodiments are tobe understood as providing exemplary features of varying detail of someways in which the inventive concepts may be implemented in practice.Therefore, unless otherwise specified, the features, components,modules, layers, films, panels, regions, and/or aspects, etc.(hereinafter individually or collectively referred to as “elements”), ofthe various embodiments may be otherwise combined, separated,interchanged, and/or rearranged without departing from the inventiveconcepts.

The use of cross-hatching and/or shading in the accompanying drawings isgenerally provided to clarify boundaries between adjacent elements. Assuch, neither the presence nor the absence of cross-hatching or shadingconveys or indicates any preference or requirement for particularmaterials, material properties, dimensions, proportions, commonalitiesbetween illustrated elements, and/or any other characteristic,attribute, property, etc., of the elements, unless specified. Further,in the accompanying drawings, the size and relative sizes of elementsmay be exaggerated for clarity and/or descriptive purposes. When anexemplary embodiment may be implemented differently, a specific processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order. Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, connected to, or coupled to the other element or layer orintervening elements or layers may be present. When, however, an elementor layer is referred to as being “directly on,” “directly connected to,”or “directly coupled to” another element or layer, there are nointervening elements or layers present. To this end, the term“connected” may refer to physical, electrical, and/or fluid connection,with or without intervening elements. Further, the D1-axis, the D2-axis,and the D3-axis are not limited to three axes of a rectangularcoordinate system, such as the x, y, and z-axes, and may be interpretedin a broader sense. For example, the D1-axis, the D2-axis, and theD3-axis may be perpendicular to one another, or may represent differentdirections that are not perpendicular to one another. For the purposesof this disclosure, “at least one of X, Y, and Z” and “at least oneselected from the group consisting of X, Y, and Z” may be construed as Xonly, Y only, Z only, or any combination of two or more of X, Y, and Z,such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

Although the terms “first,” “second,” etc. may be used herein todescribe various types of elements, these elements should not be limitedby these terms. These terms are used to distinguish one element fromanother element. Thus, a first element discussed below could be termed asecond element without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,”“above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), andthe like, may be used herein for descriptive purposes, and, thereby, todescribe one elements relationship to another element(s) as illustratedin the drawings. Spatially relative terms are intended to encompassdifferent orientations of an apparatus in use, operation, and/ormanufacture in addition to the orientation depicted in the drawings. Forexample, if the apparatus in the drawings is turned over, elementsdescribed as “below” or “beneath” other elements or features would thenbe oriented “above” the other elements or features. Thus, the exemplaryterm “below” can encompass both an orientation of above and below.Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90degrees or at other orientations), and, as such, the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. It is also noted that, as used herein, the terms“substantially,” “about,” and other similar terms, are used as terms ofapproximation and not as terms of degree, and, as such, are utilized toaccount for inherent deviations in measured, calculated, and/or providedvalues that would be recognized by one of ordinary skill in the art.

Various exemplary embodiments are described herein with reference tosectional and/or exploded illustrations that are schematic illustrationsof idealized exemplary embodiments and/or intermediate structures. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should notnecessarily be construed as limited to the particular illustrated shapesof regions, but are to include deviations in shapes that result from,for instance, manufacturing. In this manner, regions illustrated in thedrawings may be schematic in nature and the shapes of these regions maynot reflect actual shapes of regions of a device and, as such, are notnecessarily intended to be limiting.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and should not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

FIG. 1A is a top view of a light emitting device according to anexemplary embodiment, FIG. 1B is a cross-sectional view taken along lineA-A′ of FIG. 1A, and FIG. 1C is a perspective view of a portion of thelight emitting device shown in FIG. 1A. FIG. 1D is a cross-sectionalview of a light emitting device shown in FIG. 1A according to anotherexemplary embodiment.

Referring to FIGS. 1A to 1D, a light emitting device may include a firstlight emitting part LE1, a first bonding part AC1, a second lightemitting part LE2, a second bonding part AC2, and a third light emittingpart LE3, which are vertically stacked one over another.

The first light emitting part LE1 may include a first n-typesemiconductor layer 102, a first active layer 104, a first p-typesemiconductor layer 106, and a first transparent electrode 108. Thesecond light emitting part LE2 may include a second n-type semiconductorlayer 202, a second active layer 204, a second p-type semiconductorlayer 206, and a second transparent electrode 208. The third lightemitting part LE3 may include a third n-type semiconductor layer 302, athird active layer 304, a third p-type semiconductor layer 306, and athird transparent electrode 308.

According to an exemplary embodiment, each of the first n-typesemiconductor layer 102, the second n-type semiconductor layer 202, andthe third n-type semiconductor layer 302 may include a Si-doped galliumnitride-based semiconductor layer, and each of the first p-typesemiconductor layer 106, the second p-type semiconductor layer 206, andthe third p-type semiconductor layer 306 may include a Mg-doped galliumnitride-based semiconductor layer. Each of the first active layer 104,the second active layer 204, and the third active layer 304 may includea multi-quantum well (MQW), and the composition ratio thereof may bedetermined to emit light of a desired peak wavelength. Each of the firsttransparent electrode 108, the second transparent electrode 208, and thethird transparent electrode 308 may include a transparent conductiveoxide, such as a tin oxide (SnO), an indium oxide (InO2), a zinc oxide(ZnO), an indium tin oxide (ITO), or an indium tin zinc oxide (ITZO).

According to an exemplary embodiment, each of the first light emittingpart LE1, the second light emitting part LE2, and the third lightemitting part LE3 may emit light having different wavelengths. Thestacking sequence of the first light emitting part LE1, the second lightemitting part LE2, and the third light emitting part LE3 is notparticularly limited, and may be variously modified, which will bedescribed in more detail later.

The first light emitting part LE1 may include a first mesa structureMS1, such that a portion of the first n-type semiconductor layer 102 isexposed in a vertically stacked structure including the first n-typesemiconductor layer 102, the first active layer 104, the first p-typesemiconductor layer 106, and the first transparent electrode 108.

The first mesa structure MS1 extends in a first direction DR1.Hereafter, a “width” refers to a distance measured in a second directionDR2 perpendicular to the first direction DR1, and a “thickness” refersto a distance measured in a third direction DR3 perpendicular to each ofthe first direction DR1 and the second direction DR2.

The first light emitting part LE1 may include a first mesa area MSA1where the first mesa structure MS1 is disposed, and a first bonding areaACA1 separated from the first mesa area MSA1 by a preset distance. Thefirst mesa area MSA1 may have a first width WD1, and the first bondingarea ACA1 may have a second width WD2 greater than the first width WD1.The first mesa structure MS1 including the first active layer 104 mayhave a first thickness TH1.

One sidewall of the first mesa structure MS1 may be substantiallycoplanar with one sidewall of the first n-type semiconductor layer 102,and may be substantially vertical. The other sidewall of the first mesastructure MS1 which faces away from the one surface may be disposed onthe top surface of the middle portion of the first n-type semiconductorlayer 102, and may have an inclined structure. In this case, the firstactive layer 104 may have a width greater than the first p-typesemiconductor layer 106, and the first p-type semiconductor layer 106may have a width greater than the first transparent electrode 108. Thefirst width WD1 of the first mesa structure MS1 may refer to the widthof the first active layer 104.

The first bonding part AC1 may be disposed on the first bonding areaACA1. As the first bonding area ACA1 has the second width WD2, the firstbonding part AC1 may also have the second width WD2. The first bondingpart AC1 may be separated from the first mesa structure MS1 by a presetdistance.

The first bonding part AC1 may bond and electrically couple the firstlight emitting part LE1 and the second light emitting part LE2 to eachother. The first bonding part AC1 may include a material, which has anelectrical conductivity and a bonding property, such as Al, Au, In, Sn,Ti, Ni, Ag, Cr, W, TiW, Mo, Cu, TiCu, AuSn, and InSn. The first bondingpart AC1 may electrically couple the first bonding area ACA1 (e.g., asurface facing the second light emitting part LE2) in the first n-typesemiconductor layer 102 of the first light emitting part LE1 to the backsurface (e.g., a surface facing the first light emitting part LE1) ofthe second n-type semiconductor layer 202 of the second light emittingpart LE2.

According to an exemplary embodiment, the first bonding part AC1 mayhave a second thickness TH2, and the second thickness TH2 may be greaterthan or equal to the first thickness TH1. Since the first thickness TH1is the thickness of the first mesa structure MS1 including the firstactive layer 104, and the first bonding part AC1 has a thickness greaterthan the first mesa structure MS1, the first bonding part AC1 may bethicker than the first active layer 104. In addition, since the firstactive layer 104 faces one sidewall of the first bonding part AC1 andthe first bonding part AC1 includes metal, light generated from thefirst active layer 104 may be reflected by the first bonding part AC1.In this manner, light generated from the first active layer 104 may beprevented from being incident on the second active layer 204 or thethird active layer 304, without an additional color filter or a lightblocking layer.

The second light emitting part LE2 may be positioned over the firstbonding area ACA1 of the first light emitting part LE1 where the firstbonding part AC1 is disposed. Since the first bonding area ACA1 has thesecond width WD2, the entire width of the second light emitting part LE2may have the second width WD2.

The second light emitting part LE2 may include a second mesa structureMS2, which exposes a portion of the second n-type semiconductor layer202 in a vertically stacked structure including the second n-typesemiconductor layer 202, the second active layer 204, the second p-typesemiconductor layer 206, and the second transparent electrode 208. Thesecond mesa structure MS2 may extend in the first direction DR1, may beseparated by a preset distance from the first mesa structure MS1, andmay be disposed side by side with the first mesa structure MS1.

In this manner, since the second mesa structure MS2 does not overlapwith the first mesa structure MS1 in the third direction DR3, a portionof light emitted in the third direction DR3 among from the first activelayer 104 does not exert an influence on the second active layer 204 ofthe second mesa structure MS2. As such, a color filter or a lightblocking layer may be obviated between the first light emitting part LE1and the second light emitting part LE2 in the third direction DR3. Thefirst active layer 104 is included in the first mesa structure MS1, andis separated by the preset distance from the second mesa structure MS2in the second direction DR2, and the first light emitting part LE1 andthe second light emitting part LE2 may be separated by the first bondingpart AC1 in the third direction DR3. As such, since the second activelayer 204 is sufficiently separated vertically and horizontally from thefirst active layer 104, light emitted from the second active layer 204may not exert an influence on the first active layer 104.

A light emitting device may generally have a structure, in which asecond light emitting part is vertically stacked on a first lightemitting part, such that a first active layer and a second active layeroverlap with each other. In this case, when the direction of the secondlight emitting part LE2 is a light extraction direction, the wavelengthof light generated from the second light emitting part should be longerthan the wavelength of light generated from the first light emittingpart LE1. According to the illustrated exemplary embodiment, since thefirst active layer 104 and the second active layer 204 do not to overlapwith each other, the first light emitting part LE1 and the second lightemitting part LE2 may be stacked one over another regardless of awavelength of light emitted therefrom. More particularly, the firstlight emitting part LE1 emitting a longer wavelength of light may bedisposed on the second light emitting part LE2 emitting a shorterwavelength of light, or vice versa.

The second light emitting part LE2 may include a second mesa area MSA2where the second mesa structure MS2 is positioned, and a second bondingarea ACA2 separated from the second mesa area MSA2 by a preset distance.The second mesa structure MS2 including the second active layer 204 mayhave a third thickness TH3. The second mesa area MSA2 may havesubstantially the same first width WD1 as the first mesa area MSA1, andthe second bonding area ACA2 may also have the first width WD1.

One sidewall of the second mesa structure MS2 may be substantiallycoplanar with one sidewall of the second n-type semiconductor layer 202,and may be substantially vertical. The other sidewall of the second mesastructure MS2 which faces away from the one surface may be disposed onthe top surface of the middle portion of the second n-type semiconductorlayer 202, and may have an inclined structure. In this case, the secondactive layer 204 may have a width greater than the second p-typesemiconductor layer 206, and the second p-type semiconductor layer 206may have a width greater than the second transparent electrode 208. Thefirst width WD1 of the second mesa structure MS2 may refer to the widthof the second active layer 204.

The second bonding part AC2 may be disposed on the second bonding areaACA2. Since the second bonding area ACA2 has the first width WD1, thesecond bonding part AC2 may also have the first width WD1. The secondbonding part AC2 may be separated from the second mesa structure MS2 bya preset distance.

The second bonding part AC2 may bond and electrically couple the secondlight emitting part LE2 and the third light emitting part LE3 to eachother. The second bonding part AC2 may include a material, which has anelectrical conductivity and a bonding property, such as Al, Au, In, Sn,Ti, Ni, Ag, Cr, W, TiW, Mo, Cu, TiCu, AuSn, and InSn. The second bondingpart AC2 may electrically couple the second bonding area ACA2 (e.g., asurface facing the third light emitting part LE3) in the second n-typesemiconductor layer 202 of the second light emitting part LE2 to theback surface (e.g., a surface facing the second light emitting part LE2)of the third n-type semiconductor layer 302 of the third light emittingpart LE3 with each other. The first bonding part AC1 may electricallycouple the first n-type semiconductor layer 102 of the first lightemitting part LE1 and the second n-type semiconductor layer 202 of thesecond light emitting part LE2 with each other, and the second bondingpart AC2 may electrically couple the second n-type semiconductor layer202 of the second light emitting part LE2 and the third n-typesemiconductor layer 302 of the third light emitting part LE3 with eachother. As such, the first n-type semiconductor layer 102, the secondn-type semiconductor layer 202, and the third n-type semiconductor layer302 may be electrically coupled with one another by the first bondingpart AC1 and the second bonding part AC2.

According to an exemplary embodiment, the second bonding part AC2 mayhave a fourth thickness TH4, and the fourth thickness TH4 may be greaterthan or equal to the third thickness TH3. Since the second active layer204 faces one sidewall of the second bonding part AC2 and the secondbonding part AC2 includes metal, light generated from the second activelayer 204 may be reflected by the second bonding part AC2. In thismanner, light generated from the second active layer 204 may beprevented from being incident on the third active layer 304, without anaddition color filter or a light blocking layer.

The third light emitting part LE3 may have a structure, in which thethird n-type semiconductor layer 302, the third active layer 304, thethird p-type semiconductor layer 306, and the third transparentelectrode 308 are stacked one over another with substantially the samewidth. In particular, the third light emitting part LE3 may not have amesa structure. The light emitting area of the third light emitting partLE3 may be substantially the same as the entire area of the third lightemitting part LE3.

The third light emitting part LE3 may extend in the first direction DR1,may be separated from the first mesa structure MS1 and the second mesastructure MS2 by preset distances, and may be disposed side by side withthe first mesa structure MS1 and the second mesa structure MS2. Sincethe third light emitting part LE3 does not overlap with the second mesastructure MS2 including the second active layer 204 and the first mesastructure MS1 including the first active layer 104, light generated fromthe first active layer 104 and the second active layer 204 may not exertan influence on the third active layer 304 of the third light emittingpart LE3. As such, a color filter or a light blocking layer may beobviated between the first light emitting part LE1, the second lightemitting part LE2, and the third light emitting part LE3. The thirdactive layer 304 disposed over the second bonding area ACA2 and thesecond active layer 204 disposed in the second mesa area MSA2 may beseparated in the second direction DR2 by a distance substantially thesame as a distance between the second bonding area ACA2 and the secondmesa area MSA2. The third active layer 304 may be separated from thesecond active layer 204 in the third direction DR3 by the fourththickness TH4 of the second bonding part AC2 and the thickness of thethird n-type semiconductor layer 302. In this manner, as the thirdactive layer 304 is sufficiently separated in the vertical andhorizontal directions from the second active layer 204, light generatedfrom the third active layer 304 may not exert an influence on the secondactive layer 204.

A light emitting device may generally have a structure, in which asecond light emitting part and a third light emitting part arevertically stacked on a first light emitting part LE1, such that a firstactive layer, a second active layer, and a third active layer 304overlap with one another. In this case, when the direction of the thirdlight emitting part LE3 is a light extraction direction, the wavelengthof light generated from the first light emitting part LE1 should belonger than the wavelength of light generated from the second lightemitting part LE2, and the wavelength of light generated from the secondlight emitting part LE2 should be longer than the wavelength of lightgenerated from the third light emitting part LE3. According to theillustrated exemplary embodiment, since the first active layer 104, thesecond active layer 204, and the third active layer 304 do not tooverlap with one another, the first light emitting part LE1, the secondlight emitting part LE2, and the third light emitting part LE3 may bestacked one over another regardless of a wavelength of light emittedtherefrom.

The third light emitting part LE3 may be positioned over the secondbonding area ACA2 of the second light emitting part LE2, in which thesecond bonding part AC2 is disposed. As the second bonding area ACA2 hasthe first width WD1, the entire width of the third light emitting partLE3 may be the first width WD1. As described above, the light emittingarea of the first light emitting part LE1 may have the first width WD1,the light emitting area of the second light emitting part LE2 may havethe first width WD1, and the light emitting area of the third lightemitting part LE3 may have the first width WD1. In this manner, as thelight emitting areas of the respective first light emitting part LE1,second light emitting part LE2, and third light emitting part LE3 havesubstantially the same size, the amount of light generated from therespective first light emitting part LE1, second light emitting partLE2, and third light emitting part LE3 may be substantially the same,and thus, reliability in generating a color may be improved.

The light emitting device may further include a first pad P1electrically coupled with the first transparent electrode 108 of thefirst light emitting part LE1, a second pad P2 electrically coupled withthe second transparent electrode 208 of the second light emitting partLE2, a third pad P3 electrically coupled with the third transparentelectrode 308 of the third light emitting part LE3, and a common pad CPelectrically coupled with the first n-type semiconductor layer 102, thesecond n-type semiconductor layer 202, and the third n-typesemiconductor layer 302.

In the light emitting device according to the illustrated exemplaryembodiment, the direction of the third light emitting part LE3 may be alight extraction direction. In order for light to be maximally emittedfrom the light extraction surface, each of the first pad P1, the secondpad P2 and the third pad P3 may have a minimal area. The common pad CPmay be disposed on the other surface of the first n-type semiconductorlayer 102. For example, the common pad CP may entirely cover the firstn-type semiconductor layer 102, without being limited thereto. Asanother example, the common pad CP may partially covers the first n-typesemiconductor layer 102.

Referring to FIG. 1D, according to another exemplary embodiment, thethird light emitting part LE3 is stacked over the second light emittingpart LE2, and the second light emitting part LE2 is stacked over thefirst light emitting part LE1. As such, the surface levels of the firstlight emitting part LE1, the second light emitting part LE2, and thethird light emitting part LE3 may be different from one another. Inorder to dispose the first pad P1, the second pad P2, and the third padP3 at substantially the same level, the light emitting device mayfurther include a passivation layer PAL, which covers the first lightemitting part LE1, the second light emitting part LE2, and the thirdlight emitting part LE3 and has a top surface substantially the same asthe top surface of the third transparent electrode 308. The passivationlayer PAL may include, for example, SOG (silicon on glass), epoxy,polyimide, SUB, BCB (benzo cyclo butene), or others, which has a highlight transmittance and a flowable characteristic. The respective firstpad P1, second pad P2, and third pad P3 may be disposed on thepassivation layer PAL. The first pad P1 may be electrically coupled withthe first transparent electrode 108 through a first via structure VS1,the second pad P2 may be electrically coupled with the secondtransparent electrode 208 through a second via structure VS2, and thethird pad P3 may be directly contacting the third transparent electrode308. Each of the first via structure VS1 and the second via structureVS2 may have a width that gradually decreases in a downward directionand an inclined sidewall. Each of the first pad P1, the second pad P2,and the third pad P3 may include Au, for example. Each of the first viastructure VS1 and the second via structure VS2 may include at least oneof Au, Al, Ni, Ti, Cr, Cu, W, TiW, Mo, Cu, TiCu, AuSn, and InSn.

FIGS. 2A to 2C are cross-sectional views of a light emitting deviceaccording to an exemplary embodiment.

Referring to FIGS. 2A to 2C, a light emitting device may include a firstlight emitting part LE1, a first bonding part AC1, a second lightemitting part LE2, a second bonding part AC2, and a third light emittingpart LE3, which are sequentially disposed on a substrate 100.

The substrate 100 may be a substrate capable of growing a galliumnitride-based semiconductor layer thereon, which may include a sapphire(Al₂O₃), a silicon carbide (SiC), a gallium nitride (GaN), an indiumgallium nitride (InGaN), an aluminum gallium nitride (AlGaN), analuminum nitride (AlN), a gallium oxide (Ga₂O₃), or silicon. Also, thesubstrate 100 may be a patterned sapphire substrate.

The first light emitting part LE1 is disposed on one surface of thesubstrate 100. The first light emitting part LE1 may include a firstn-type semiconductor layer 102 and a first mesa structure MS1, whichexposes a portion of the first n-type semiconductor layer 102 on avertically stacked structure including the first n-type semiconductorlayer 102, a first active layer 104, a first p-type semiconductor layer106, and a first transparent electrode 108.

The second light emitting part LE2 may include a second n-typesemiconductor layer 202 and a second mesa structure MS2, which exposes aportion of the second n-type semiconductor layer 202 on a verticallystacked structure including the second n-type semiconductor layer 202, asecond active layer 204, a second p-type semiconductor layer 206, and asecond transparent electrode 208.

The third light emitting part LE3 may include a third n-typesemiconductor layer 302, a third active layer 304, a third n-typesemiconductor layer 302, and a third transparent electrode 308.According to the illustrated exemplary embodiment, the third lightemitting part LE3 shown in FIGS. 2A and 2B does not have a mesastructure, and the third n-type semiconductor layer 302, the thirdactive layer 304, the third p-type semiconductor layer 306, and thethird transparent electrode 308 may have substantially the same width.According to another exemplary embodiment, the third light emitting partLE3 may include a third mesa structure MS3, as shown in FIG. 2C, whichexposes a portion of the third n-type semiconductor layer 302 on avertically stacked structure including the third n-type semiconductorlayer 302, the third active layer 304, the third p-type semiconductorlayer 306, and the third transparent electrode 308.

Referring to FIGS. 2A to 2C, the light emitting device may furtherinclude a first pad P1 which is electrically coupled with the firsttransparent electrode 108, a second pad P2 which is electrically coupledwith the second transparent electrode 208, and a third pad P3 which iselectrically coupled with the third transparent electrode 308.

The first n-type semiconductor layer 102 of the first light emittingpart LE1 and the second n-type semiconductor layer 202 of the secondlight emitting part LE2 may be electrically coupled with each other bythe first bonding part AC1, and the second n-type semiconductor layer202 of the second light emitting part LE2 and the third n-typesemiconductor layer 302 of the third light emitting part LE3 may beelectrically coupled with each other by the second bonding part AC2. Thelight emitting device may further include a common pad CP, whichelectrically couples the first n-type semiconductor layer 102, thesecond n-type semiconductor layer 202, and the third n-typesemiconductor layer 302.

According to an exemplary embodiment shown in FIG. 2A, the common pad CPmay be brought into electrical contact with the first n-typesemiconductor layer 102 on the first light emitting part LE1. As such,the common pad CP may be electrically coupled with the second n-typesemiconductor layer 202 and the third n-type semiconductor layer 302through the first n-type semiconductor layer 102. In this case, sincethe features of the light emitting device are substantially the same asthe features described of the light emitting device described above withreference to FIG. 1A, except that the first n-type semiconductor layer102 of the first light emitting part LE1 has a width greater than thewidth of the first n-type semiconductor layer 102 of the first lightemitting part LE1 shown in FIG. 1A to dispose the common pad CP thereon,repeated descriptions thereof will be omitted to avoid redundancy.

According to another exemplary embodiment shown in FIG. 2B, the commonpad CP may be brought into electrical contact with the second n-typesemiconductor layer 202 on the second light emitting part LE2. As such,the common pad CP may be electrically coupled with the first n-typesemiconductor layer 102 and the third n-type semiconductor layer 302through the second n-type semiconductor layer 202. In this case, sincethe features of the light emitting device are substantially the same asthe features of the light emitting device described above with referenceto FIG. 1A, except that the second n-type semiconductor layer 202 of thesecond light emitting part LE2 has a width greater than the width of thesecond n-type semiconductor layer 202 of the second light emitting partLE2 shown in FIG. 1A to dispose the common pad CP thereon, repeateddescriptions thereof will be omitted.

According to still another exemplary embodiment shown in FIG. 2C, thecommon pad CP may be brought into electrical contact with the thirdn-type semiconductor layer 302 on the third light emitting part LE3. Assuch, the common pad CP may be electrically coupled with the firstn-type semiconductor layer 102 and the second n-type semiconductor layer202 through the third n-type semiconductor layer 302. Since the featuresof the light emitting device are substantially the same as the featuresof the light emitting device described above with reference to FIG. 1A,except that the third light emitting part LE3 includes the third mesastructure MS3 exposing the third n-type semiconductor layer 302, suchthat the common pad CP is disposed on the third n-type semiconductorlayer 302 of the third light emitting part LE3 as shown in FIG. 2C,repeated descriptions thereof will be omitted.

In the illustrated exemplary embodiments, since the features of thefirst light emitting part LE1, the first bonding part AC1, the secondlight emitting part LE2, the second bonding part AC2, the third lightemitting part LE3, the first pad P1, the second pad P2, the third pad P3and the common pad CP are substantially the same as those made abovewith reference to FIGS. 1A to 1D, repeated descriptions thereof will beomitted to avoid redundancy.

FIG. 3A is a plan view of a light emitting device according to anexemplary embodiment, and FIG. 3B is a cross-sectional view taken alongline A-A′ of FIG. 3A.

Referring to FIGS. 3A and 3B, a light emitting device may include afirst light emitting part LE1, a second light emitting part LE2, a thirdlight emitting part LE3, a bonding part, a first pad P1, a second padP2, and a third pad P3.

The first light emitting part LE1 may include a first n-typesemiconductor layer 102 and a first mesa structure MS1, which exposes aportion of the first n-type semiconductor layer 102 on a verticallystacked structure including the first n-type semiconductor layer 102, afirst active layer 104, a first p-type semiconductor layer 106, and afirst transparent electrode 108. The first mesa structure MS1 may extendin a first direction DR1, and may have a first width WD1 in a seconddirection DR2.

The second light emitting part LE2 may include a second n-typesemiconductor layer 202, a second active layer 204, a second p-typesemiconductor layer 206, and a second transparent electrode 208 whichare vertically stacked. The second light emitting part LE2 does not havea mesa structure. The second light emitting part LE2 may extend in thesecond direction DR2, and may have the first width WD1 in the firstdirection DR1.

The third light emitting part LE3 may include a third n-typesemiconductor layer 302, a third active layer 304, a third p-typesemiconductor layer 306, and a third transparent electrode 308, whichare vertically stacked. The third light emitting part LE3 does not havea mesa structure. The third light emitting part LE3 may extend in thesecond direction DR2, and may have the first width WD1 in the firstdirection DR1.

The light emitting device may have a structure, in which the secondlight emitting part LE2 and the third light emitting part LE3 areseparated from each other on the first light emitting part LE1. Inparticular, the second light emitting part LE2 and the third lightemitting part LE3 may be separated from each other on the first n-typesemiconductor layer 102, and may also be separated from the first mesastructure MS1.

For example, the second light emitting part LE2 and the third lightemitting part LE3 may be bonded and electrically coupled with each otherby the bonding part on the first n-type semiconductor layer 102 of thefirst light emitting part LE1. As such, the first n-type semiconductorlayer 102 may be brought into contact with and electrically coupled withthe second n-type semiconductor layer 202 of the second light emittingpart LE2, and may be brought into contact with and electrically coupledwith the third n-type semiconductor layer 302 of the third lightemitting part LE3 by the bonding part.

As another example, the bonding part may include a first pattern, whichbonds and electrically couples the second light emitting part LE2 andthe first n-type semiconductor layer 102 of the first light emittingpart LE1, and a second pattern, which is separated from the firstpattern, bonds and electrically couples the third light emitting partLE3 and the first n-type semiconductor layer 102 of the first lightemitting part LE1.

A light blocking layer BL may be additionally provided between thesecond light emitting part LE2 and the third light emitting part LE3,such that light generated from the second active layer 204 may not beincident on the third light emitting part LE3 or light generated fromthe third active layer 304 may not be incident on the second lightemitting part LE2. As the light blocking layer BL, for example, a blackmatrix may be used.

The first pad P1 may be brought into electrical contact with the firsttransparent electrode 108 of the first light emitting part LE1, thesecond pad P2 may be brought into electrical contact with the secondtransparent electrode 208 of the second light emitting part LE2, and thethird pad P3 may be brought into electrical contact with the thirdtransparent electrode 308 of the third light emitting part LE3. A commonpad CP may be disposed on the bottom surface of the first n-typesemiconductor layer 102 of the first light emitting part LE1. Forexample, the common pad CP may be disposed to completely cover thebottom surface of the first n-type semiconductor layer 102 of the firstlight emitting part LE1. As another example, the common pad CP may bebrought into partial contact with the first n-type semiconductor layer102 of the first light emitting part LE1. Further, as shown in FIGS. 2Ato 2C, the common pad CP may be brought into electrical contact with thefirst n-type semiconductor layer 102, may be brought into electricalcontact with the second n-type semiconductor layer 202, or may bebrought into electrical contact with the third n-type semiconductorlayer 302. In each of these cases, the structures of the first lightemitting part LE1, the second light emitting part LE2, and the thirdlight emitting part LE3 may be anyone of those described above withreference to FIGS. 2A to 2C.

Hereinafter, a method for manufacturing the light emitting devicedescribed above with reference to FIGS. 1A to 1C will be exemplarilydescribed.

FIGS. 4A to 16A are top views illustrating a method for manufacturing alight emitting device according to an exemplary embodiment, and FIGS. 4Ato 16B are cross-sectional views taken along lines A-A′ of correspondingtop views shown in FIGS. 4A to 16A, respectively.

Referring to FIGS. 4A and 4B, a plurality of first light emitting partsLE1 may be formed on a first substrate 100.

In more detail, a first n-type semiconductor layer 102, a first activelayer 104, a first p-type semiconductor layer 106, and a firsttransparent electrode 108 may be sequentially formed on the firstsubstrate 100. By etching the first transparent electrode 108, the firstp-type semiconductor layer 106, and the first active layer 104, thefirst light emitting parts LE1 each including a first mesa structureMS1, in which the first active layer 104, the first p-type semiconductorlayer 106, and the first transparent electrode 108 are verticallystacked, may be formed.

The first light emitting part LE1 may include a first mesa area MSA1where the first mesa structure MS1 is disposed, and a first bonding areaACA1 which is separated from the first mesa area MSA1 by a presetdistance. The first mesa area MSA1 may have a first width WD1, and thefirst bonding area ACA1 may have a second width WD2 greater than thefirst width WD1.

Referring to FIGS. 5A and 5B, a first insulation layer 110 may be formedon the first substrate 100, on which the first light emitting parts LE1are formed. The first insulation layer 110 may include SiO₂, SiN_(x),Al₂O₃, or others. By etching the first insulation layer 110, firstopenings OP1 exposing the first transparent electrodes 108 and secondopenings OP2 exposing the first bonding areas ACA1 may be formed.

Alternatively, in some exemplary embodiments, rather than forming thefirst openings OP1 on the first insulation layer 110, which is disposedon the first transparent electrodes 108, a plurality of through holesmay be formed. The plurality of through holes may be uniformly arranged.

Referring to FIGS. 6A and 6B, first pads P1 and first contact patterns114 may be formed on the first openings OP1 and the second openings OP2,respectively.

In more detail, a first metal layer may be formed on the first lightemitting parts LE1 formed with the first openings OP1 and the secondopenings OP2. The first metal layer may include at least one metallicmaterial, such as Ni, Ag, Au, Pt, Ti, Al, Cr, W, TiW, Mo, Cu, or TiCu.By patterning the first metal layer, the first pads P1 may be formed onthe first openings OP1 and the first contact patterns 114 may be formedon the second openings OP2. Each of the first transparent electrodes 108may be applied with a positive voltage through each of the first padsP1. The first contact patterns 114 may be respectively bonded withsecond light emitting parts LE2 to be formed thereon, therebyelectrically coupling the first light emitting parts LE1 and the secondlight emitting parts LE2.

Referring to FIGS. 7A and 7B, a plurality of second light emitting partsLE2 may be formed on a second substrate 200.

In more detail, a second n-type semiconductor layer 202, a second activelayer 204, a second p-type semiconductor layer 206, and a secondtransparent electrode 208 may be sequentially formed on the secondsubstrate 200. By etching the second transparent electrode 208, thesecond p-type semiconductor layer 206, and the second active layer 204,second mesa structures MS2, in which the second active layer 204, thesecond p-type semiconductor layer 206, and the second transparentelectrode 208 are vertically stacked may be formed on the second n-typesemiconductor layer 202.

By etching the second n-type semiconductor layer 202, the second lightemitting parts LE2 each including the second n-type semiconductor layer202 and the second mesa structure MS2, which exposes a portion of thesecond n-type semiconductor layer 202, may be formed. The second lightemitting part LE2 may include a second mesa area MSA2 where the secondmesa structure MS2 is disposed, and a second bonding area ACA2 which isseparated from the second mesa area MSA2 by a preset distance. Thesecond mesa area MSA2 may have substantially the same first width WD1 asthe first mesa area MSA1, and the second bonding area ACA2 may also havethe first width WD1.

According to an exemplary embodiment, if the structure and the size ofthe second substrate 200 are substantially the same as those of thefirst substrate 100, each of the second light emitting parts LE2 may beformed on the second substrate 200 to correspond to the first bondingarea ACA1 of each first light emitting part LE1 on the first substrate100.

Referring to FIGS. 8A and 8B, a second insulation layer 210 may beformed on the second substrate 200, on which the second light emittingparts LE2 are formed. The second insulation layer 210 may include SiO₂,SiN_(x), Al₂O₃, or others. By etching the second insulation layer 210,third openings OP3 exposing the second transparent electrodes 208 andfourth openings OP4 exposing the second bonding areas ACA2 may beformed.

Alternatively, rather than forming the third openings OP3 in the secondinsulation layer 210, which is disposed on the second transparentelectrodes 208, a plurality of through holes may be formed. Theplurality of through holes may be uniformly arranged.

Referring to FIGS. 9A and 9B, second pads P2 and second contact patterns214 may be formed on the third openings OP3 and the fourth openings OP4,respectively.

In more detail, a second metal layer may be formed on the second lightemitting parts LE2, which are formed with the third openings OP3 and thefourth openings OP4. The second metal layer may include at least onemetallic material, such as Ni, Ag, Au, Pt, Ti, Al, Cr, W, TiW, Mo, Cu,or TiCu. By patterning the second metal layer, the second pads P2 may beformed on the third openings OP3 and the second contact patterns 214 maybe formed on the fourth openings OP4. Each of the second pads P2 mayapply a positive voltage to each of the second transparent electrodes208. The second contact patterns 214 may be respectively bonded withthird light emitting parts LE3 to be formed thereon, therebyelectrically coupling the second light emitting parts LE2 and the thirdlight emitting parts LE3.

Referring to FIGS. 10A and 10B, a first removable carrier 216 may beattached onto the second light emitting parts LE2, which are formed withthe second pads P2 and the second contact patterns 214. For example, thefirst carrier 216 may include one among a blue tape, a thermal releasetape, a UV tape, a photoresist, or a wax. After attaching the firstcarrier 216, the second substrate 200 may be removed by using a laserlift-off process, or the like.

Then, third contact patterns 218 and first bonding patterns 220 may besequentially formed on second n-type semiconductor layers 202, fromwhich the second substrate 200 is removed. Each of the third contactpatterns 218 may include Au. Each of the first bonding patterns 220 mayinclude at least one of In, Sn, Ti, and Ni.

Referring to FIGS. 11A and 11B, the second light emitting parts LE2 maybe respectively bonded onto the first light emitting parts LE1.

In more detail, by bonding the first contact patterns 114 of the firstlight emitting parts LE1 and the first bonding patterns 220 formed inthe second light emitting parts LE2, a first bonding part AC1 includingthe first contact pattern 114, the first bonding pattern 220, and thethird contact pattern 218 may be formed between each first lightemitting part LE1 and each second light emitting part LE2. In thismanner, the first bonding part AC1 may bond and electrically couple thefirst light emitting part LE1 and the second light emitting part LE2 toeach other.

After electrically bonding the first light emitting parts LE1 and thesecond light emitting parts LE2, the first carrier 216 may be removed.

Referring to FIGS. 12A and 12B, a plurality of third light emittingparts LE3 may be formed on a third substrate 300.

In more detail, a third n-type semiconductor layer 302, a third activelayer 304, a third p-type semiconductor layer 306, and a thirdtransparent electrode 308 may be sequentially formed on the thirdsubstrate 300. By etching the third transparent electrode 308, the thirdp-type semiconductor layer 306, the third active layer 304, and thethird n-type semiconductor layer 302, the third light emitting parts LE3each including the third n-type semiconductor layer 302, the thirdactive layer 304, the third p-type semiconductor layer 306, and thethird transparent electrode 308, which are sequentially stacked one overanother may be formed. Each of the third light emitting parts LE3 mayhave the first width WD1.

According to an exemplary embodiment, if the structure and the size ofthe third substrate 300 are substantially the same as those of each ofthe first substrate 100 and the second substrate 200, each of the thirdlight emitting parts LE3 may be formed on the third substrate 300 tocorrespond to the second bonding area ACA2 of each second light emittingpart LE2 on the second substrate 200.

Referring to FIGS. 13A and 13B, a third insulation layer 310 may beformed on the third substrate 300, on which the third light emittingparts LE3 are formed. The third insulation layer 310 may include SiO₂,SiN_(x), Al₂O₃, or others. By etching the third insulation layer 310,fifth openings OP5 exposing the third transparent electrodes 308 may beformed.

Alternatively, rather than forming the fifth openings OP5 in the thirdinsulation layer 310, which is disposed on the third transparentelectrodes 308, a plurality of through holes may be formed. Theplurality of through holes may be uniformly arranged.

Referring to FIGS. 14A and 14B, third pads P3 may be formed on the fifthopenings OP5. The third pads P3 may include at least one metallicmaterial of Ni, Ag, Au, Pt, Ti, Al, Cr, W, TiW, Mo, Cu, or TiCu. Thethird pads P3 may apply a positive voltage to the third transparentelectrodes 308.

Referring to FIGS. 15A and 15B, a second removable carrier 314 may beattached onto the third light emitting parts LE3 formed with the thirdpads P3. For example, the second carrier 314 may include one among ablue tape, a thermal release tape, a UV tape, a photoresist, or a wax.After attaching the second carrier 314, the third substrate 300 may beremoved by using a laser lift-off process, or the like.

Then, fourth contact patterns 316 and second bonding patterns 318 may besequentially formed on third n-type semiconductor layers 302 from whichthe third substrate 300 is removed. Each of the fourth contact patterns316 may include at least one of Ni, Ag, Au, Pt, Ti, Al, Cr, W, TiW, Mo,Cu, or TiCu. Each of the second bonding patterns 318 may include atleast one of In, Sn, Ti and Ni.

Referring to FIGS. 16A and 16B, the third light emitting parts LE3 maybe respectively bonded onto the second light emitting parts LE2.

In more detail, by bonding the second contact patterns 214 of the secondlight emitting parts LE2 and the second bonding patterns 318 of thethird light emitting parts LE3, a second bonding part AC2 including thesecond contact pattern 214, the second bonding pattern 318, and thefourth contact pattern 316 may be formed between each second lightemitting part LE2 and each third light emitting part LE3. The secondbonding part AC2 may bond and electrically couple the second lightemitting part LE2 and the third light emitting part LE3 to each other.

After electrically bonding the second light emitting parts LE2 and thethird light emitting parts LE3, the second carrier 314 may be removed.

Referring back to FIG. 1A, after removing the first substrate 100 byusing a laser lift-off process, or the like, a common pad CP may beformed on the bottom surface of the first n-type semiconductor layer102. The common pad CP may include at least one of Ni, Ag, Au, Pt, Ti,Al, Cr, W, TiW, Mo, Cu, TiCu, Sn, In, InSn, or AuSn.

According to the exemplary embodiments, the light emitting device mayinclude a first light emitting layer, a second light emitting layer, anda third light emitting layer that are vertically stacked one overanother, such that a first active layer, a second active layer, and athird active layer do not overlap with each other, and the sizes of therespective first to third active layers are substantially the same. Assuch, light generated from the respective first to third light emittingparts may not interfere with one another, thereby improving lightreproducibility.

Although certain exemplary embodiments and implementations have beendescribed herein, other embodiments and modifications will be apparentfrom this description. Accordingly, the inventive concepts are notlimited to such embodiments, but rather to the broader scope of theappended claims and various obvious modifications and equivalentarrangements as would be apparent to a person of ordinary skill in theart.

What is claimed is:
 1. A light emitting device comprising: a first light emitting part including a first n-type semiconductor layer, and a first mesa structure including a first active layer, a first p-type semiconductor layer, and a first transparent electrode vertically stacked one over another and exposing a portion of a first surface the first n-type semiconductor layer; a second light emitting part disposed on the exposed portion of the first n-type semiconductor layer and spaced apart from the first mesa structure, and including a second n-type semiconductor layer, a second active layer, a second p-type semiconductor layer, and a second transparent electrode; and a first bonding part bonding and electrically coupling the first n-type semiconductor layer and the second n-type semiconductor layer to each other.
 2. The light emitting device according to claim 1, wherein the second light emitting part includes a second mesa structure including the second active layer, the second p-type semiconductor layer, and the second transparent electrode vertically stacked one over another, the second mesa structure exposing a portion of the second n-type semiconductor layer.
 3. The light emitting device according to claim 2, further comprising: a third light emitting part disposed on the exposed portion of the second n-type semiconductor layer, and including a third n-type semiconductor layer, a third active layer, a third p-type semiconductor layer, and a third transparent electrode; and a second bonding part bonding and electrically coupling the second and third light emitting parts to each other between the second n-type semiconductor layer and the third n-type semiconductor layer.
 4. The light emitting device according to claim 3, wherein a thickness of the second bonding part is greater than a thickness of the second active layer.
 5. The light emitting device according to claim 3, wherein the first mesa structure, the second mesa structure, and the third light emitting part have substantially the same size with each other.
 6. The light emitting device according to claim 3, further comprising: a first pad electrically coupled with the first transparent electrode; a second pad electrically coupled with the second transparent electrode; a third pad electrically coupled with the third transparent electrode; and a common pad electrically coupled with the first, second, and third n-type semiconductor layers.
 7. The light emitting device according to claim 6, wherein the common pad is disposed on a second surface of the first n-type semiconductor layer opposing the first surface.
 8. The light emitting device according to claim 6, wherein the common pad is disposed on the exposed portion of the first n-type semiconductor layer.
 9. The light emitting device according to claim 6, wherein the common pad is disposed on the exposed portion of the second n-type semiconductor layer.
 10. The light emitting device according to claim 6, wherein: the third light emitting part includes a third mesa structure including the third active layer, the third p-type semiconductor layer, and the third transparent electrode, the third mesa structure exposing a portion of the third n-type semiconductor layer; and the common pad is disposed on the exposed portion of the third n-type semiconductor layer.
 11. The light emitting device according to claim 1, further comprising a third light emitting part disposed on the exposed portion of the first n-type semiconductor layer and spaced apart from the second light emitting part, the third light emitting part including a third n-type semiconductor layer, a third active layer, a third p-type semiconductor layer, and a third transparent electrode.
 12. The light emitting device according to claim 11, further comprising a second bonding part bonding and electrically coupling the first and third light emitting parts to each other between the first n-type semiconductor layer and the third n-type semiconductor layer.
 13. The light emitting device according to claim 11, wherein the first bonding part extends between the first n-type semiconductor layer and the third n-type semiconductor layer, and bonds and electrically couples the first and third light emitting parts to each other.
 14. The light emitting device according to claim 11, wherein the first mesa structure, the second light emitting part, and the third light emitting part have substantially the same size with each other.
 15. The light emitting device according to claim 11, further comprising a light blocking layer disposed between the second and third light emitting parts on the exposed portion of the first n-type semiconductor layer.
 16. The light emitting device according to claim 1, wherein a thickness of the first bonding part is greater than a thickness of the first active layer. 